Control Of Heart Rate Flashcards
Learn about control of heart rate
1
Q
What controls heart rate
A
Pacemakers in heart walls
2
Q
What Is a pace maker
A
It is a node of specialized tissue that sends out weak electrical pulses
3
Q
What system of the body can regulate the activity of pacemakers
A
The automatic nervous system
4
Q
What are the two pace makers in the heart that control heart rate?
A
The Sino-Atrial node and the atrio- ventricular node
5
Q
Explain the steps of the two pace makers
A
- A wave of excitation from SA node spreads outward causing atria to contract and blood is forced into ventricles
- The wave is picked up by av node then the wave of excitation is conducted from av node by purkinje fibers in bundles of his to apex and heart outer walls.ensuring the ventricles contract from apex upwards and allows blood to be forced through arteries at the top of the heart
- the SA node is regulated by nerve impulses from respiratory center in the medulla oblongata of the brain the vagus nerve from medulla oblongata stimulates the sa node to slow down heart rate when heart is beating fast
6
Q
Explain the steps of the two pace makers
A
- A wave of excitation from SA node spreads outward causing atria to contract and blood is forced into ventricles
- The wave is picked up by av node then the wave of excitation is conducted from av node by purkinje fibers in bundles of his to apex and heart outer walls.ensuring the ventricles contract from apex upwards and allows blood to be forced through arteries at the top of the heart
- the SA node is regulated by nerve impulses from respiratory center in the medulla oblongata of the brain the vagus nerve from medulla oblongata stimulates the sa node to slow down heart rate when heart is beating fast
7
Q
What are the two stages in a heart’s cycle
A
Systole-where it contracts squeezing blood out of chambers.
Diastole-when it relaxes
8
Q
What is the cardiac cycle
A
The process where blood flows through the heart
